The present invention relates to distinguishing between stereo and mono audio devices (such as headset speakers). More particularly, this invention relates to controlling the output of portable multi-function devices based upon detected conditions.
The widespread popularity of mobile telephones and other portable multi-function devices (e.g., portable MP3 players, portable video players, media-capable mobile telephones) is largely due to their portability. These devices enable users to enjoy media and conduct telephone calls while on the go.
As portable multi-function devices have proliferated, so too have headsets. Headsets contain one or more speakers that can emit sound generated by a portable multi-function device. Headsets capable of emitting one channel of audio are sometimes referred to herein as “mono headsets.” Headsets that can emit more than one channel of audio are sometimes referred to herein as “stereo headsets.”
Some headsets also include one or more microphones and facilitate a conversation between two people. Headset microphones and their corresponding circuitry can convert sound, which may be produced by a user, to electrical signals which are sent to a portable multi-function device.
Stereo and mono headsets offer different advantages. For example, a stereo headset that includes two speakers is most desirable for listening to recorded media. This is because almost all commercial audio recordings divide audio among two or more stereo channels—a technique that provides a rich and pleasant listing experience. By contrast, telephone conversations only require one channel of audio, and, therefore, only require one speaker. In part, this is because telephones are primarily used for communication, rather than auditory enjoyment. Additionally, telephone users commonly engage in activities that require an awareness of one's surroundings (e.g., driving, bicycling while using a headset). For at least these reasons, some mobile telephone users prefer mono headsets.
However, a problem arises when, for example, a mono headset is used with a portable multi-function device outputting audio in stereo. Stereo audio includes two channels of sound, but mono headsets can emit only one channel of sound. A user listening to a stereo recording on a mono headset would have a severely diminished listening experience because some of the recording would not be heard.
Another problem arises when, due to defect, damage, or any other cause, one or more speakers in a headset do not operate properly. For example, a damaged or defective stereo headset may have only one operational speaker. Similarly, a damaged or defective stereo headset may have one speaker that operates properly, and another speaker that produces distorted or intermittent sound. A user listening to a stereo recording on a defective or damaged headset would have a severely diminished listening experience because distorted or intermittent sound would be produced.
Another problem arises when a headset that does not contain a microphone is used for applications requiring a microphone (e.g., telephone calls). For example, a headset lacking a microphone coupled to a mobile telephone or a portable multi-function device having mobile telephony capability cannot properly carry a telephone call because it cannot receive a user's voice. (Portable multi-function devices having mobile telephony capability, such as Apple Inc.'s iPhone™, which can be used to perform various functions, including those related to communications and entertainment, may also be referred to herein as hybrid devices. iPhone™ is a trademark owned by Apple Inc.) Because portable multi-function devices cannot automatically detect the presence or absence of a headset microphone, users are not alerted when a microphone is not present.
Yet another problem arises when, due to defect, damage, or any other cause, a headset microphone does not operate properly. For example, a damaged or defective headset microphone may fail to convey audio signals, or may convey distorted or intermittent audio signals. The user in such cases may be unaware of the malfunction.
Another problem arises in detecting and responding to a headset being connected or disconnected from a portable multi-function device. For example, some portable multi-function devices, like Apple Inc's iPod™, pause the playback of media signals when headsets are removed. (iPod™ is a trademark owned by Apple Inc.) Such portable multi-function devices utilize a mechanical switch to detect insertion or removal of a headset tip. The mechanical switch is toggled physically by the insertion or removal of the headset tip, regardless of whether a functional headset is coupled to the portable multi-function device's connector. For example, among other things, nonfunctioning headsets or even a loose wire with a headset tip would toggle the switch.